Exposure apparatus for production of integrated circuit

Abstract

An exposure apparatus for production of ICs of the type that includes a stage on which is placed a semiconductor wafer to be exposed by illumination light projecting means, and means for two-dimensionally moving the stage within a plane intersecting the illumination light at substantially right angles. The improvement comprises illumination detection means provided with a photo reception surface, and means for mounting the illumination detection means on the stage in such a manner that the photo reception surface and the surface of the semiconductor wafer on the stage to be exposed are at substantially equal height relative to the stage.

We claim: 
     
       1. In an exposure apparatus for production of integrated circuits including a stage on which a semiconductor wafer is placed for exposure by illumination light projecting means and means for two-dimensionally displacing said stage in a plane intersecting the illumination light at substantially right angles, an improvement comprising: illumination detecting means having a photo reception surface; and   means for mounting said illumination detecting means on said stage in such manner that said photo reception surface lies substantially at the same level as the exposed surface of said semiconductor wafer on said stage relative to said stage.   
     
     
       2. The improvement as set forth in claim 1, wherein said illumination light projecting means is so mounted as to illuminate a selected area on said stage and wherein said illumination detecting means is mounted out of said selected area on said stage. 
     
     
       3. The improvement as set forth in claim 2 which further comprises means for guiding said illumination detecting means into said selected area. 
     
     
       4. The improvement as set forth in claim 3, wherein said displacing means includes means for detecting the position of said illumination detecting means and means for driving said stage in response to said position detecting means. 
     
     
       5. The improvement as set forth in claim 1, wherein said mounting means includes an intercepting member having an opening therethrough that is very small in area parallel to said plane relative to the area of the photo reception surface parallel to said plane to limit the light receivable area on the photo reception surface of said illumination detecting means. 
     
     
       6. The improvement as set forth in claim 1, wherein said illumination detecting means comprises a one-dimensional photo sensor. 
     
     
       7. The improvement as set forth in claim 1, wherein said illumination detecting means comprises a two-dimensional photo sensor. 
     
     
       8. In an exposure apparatus for production of integrated circuits in which a pattern is illuminated to print an image of the pattern through an optical system onto a surface to be exposed of a semiconductor wafer having predetermined thickness, an improvement comprising: (a) a stage having a surface for supporting said semiconductor wafer thereon at a predetermined location with said semiconductor wafer surface to be exposed oriented substantially perpendicular to the optical axis of said optical system, the stage being supported to move on a two-dimensional plane substantially orthogonal to said optical axis;   (b) limiting means providing a limited area through which light passes, said limiting means being integral with said stage and positioned at a location on said stage spaced laterally away from said predetermined location;   (c) means detecting the light which passes through said limiting means to convert it into an electric signal, said detecting means having a photo reception surface that is at substantially the same level relative to said stage surface as the surface of the semiconductor wafer to be exposed; and   (d) means for detecting the position of said stage on said two-dimensional plane.   
     
     
       9. In an exposure apparatus for production of integrated circuits in which a pattern is illuminated to print an image of the pattern through an optical system onto a surface to be exposed of a semiconductor wafer, an improvement comprising: (a) a stage on which said semiconductor wafer is supported with said semiconductor wafer surface to be exposed substantially perpendicular to the optical axis of said optical system, the stage being supported to move on a two-dimensional plane substantially orthogonal to said optical axis;   (b) illumination detecting means having a photo reception surface and being provided with an intercepting member having an opening formed therethrough that is very small in area parallel to said plane relative to the area of the photo reception surface parallel to said plane to limit the light receivable area on the photo reception surface, the illumination detecting means including means to support said photo reception surface on said stage at a level substantially coincident with the level of said semiconductor wafer surface to be exposed; and   (c) means detecting the position of said stage on said two-dimensional plane.   
     
     
       10. The improvement as set forth in claim 9, wherein said illumination detecting means includes a photoelectric element for detecting the light which passes through said opening to convert it into an electric signal.